STE V1.5 32MHz BOOSTER - STATUS

[sandord]

Yeah its a small Ikea table.. also stolen from my girlfriends...

It almost sounds as if the two of you could swap appartments and have most of your stuff back

[IngoQ]

As vice president of the organization to preserve useless knowledge I cannot resist to add:

Did you know, that the IKEA Lack is almost perfectly 19" and can therefore be used as a network rack?

https://wiki.eth0.nl/index.php/LackRack

[exxos]

There will be about 8 going into my store tomorrow..

https://www.exxoshost.co.uk/atari/last/storenew/#0147

I'm not going to spend anymore time of these for the foreseeable future.

Time to move onto the V2.2 Booster boards now.

[sandord]

There will be about 8 going into my store tomorrow..

https://www.exxoshost.co.uk/atari/last/storenew/#0147

I'm not going to spend anymore time of these for the foreseeable future.

Time to move onto the V2.2 Booster boards now.

Congratulations, it must be a huge relief for you!

[exxos]

In light of recent endeavours.. While this booster is currently requiring linking back to the STE 32MHz clock and new firmware.. Oddly a firmware I created does work at 36MHz.. But this requires the CPU CLK inverting, which means the 8MHz clock is out of phase with the motherboard so I am not happy with that solution.

But also, reprogramming a 22V10 GAL hundreds of times as a total nightmare as I keep having to remove it from the socket, but it in the programmer, but it back in the socket, with my poorly fingers I just had to stop doing that.

What I have started tonight is a ATF1502 PLCC 44 PLD to 22V10 adapter... Which will basically be the same as there Altera board I did ages ago.. viewtopic.php?f=24&t=76#p202 This way I can do "in circuit programming".

But more to the point, I think the problem is the clock low times are being violated during switching transitions... I'm too lazy to take scope captures of this at the moment, but basically when switching from 32MHz to 8MHz, it always starts the 8 MHz cycle on the low part. And it always starts on the low part and finishes it in switching into 32MHz. When using the STE's 32MHz clock, this timing is always identical it is always stable. However when using a external oscillator such as 36MHz, that low period is basically random and that is that I believe where things are going wrong.

The way to solve this is to have both clocks being used to switch the frequencies, however a limitation of the 22V10 is it can only have one clock input to drive the flip-flops, which has to be 32MHz, and there is no way to even manually create this delay as the 22V10 simply doesn't have enough LA's or IOs. So moving to more "mature" PLD such as the ATF1502 is the only way I can create proper sync logic.

I have done some tests by delaying the 8MHz clock by a "double inverter" and also use that in the sync logic, basically just adding a few ns (about 40ns) so it stretches the clock edges out of it, so when I sync to them, they are actually slightly out of sync to what the ST clock is doing. Basically a type of "pulse stretcher" so it is just enough to get the 36MHz running stable and the hard drive also works perfectly as well. But it is all just too much logic to fit into the 22V10 to do it all properly.

So future V1.5 batches will have to be linked to the STE's 32MHz clock like the V1 booster. I don't know when I will get chance to do more boards, I will be have to a third party to assemble a few.. Meanwhile I will finish designing this ATF adapter board, and in a couple of weeks time I can experiment with the code a lot better and see if I can bring back a 36MHz or 40MHz booster. Work on this will probably be somewhat slow though.

EDIT:

Crappy adapter PCB done.

e671b9941312b1daf105d14bbac803e7.png (146.54 KiB) Viewed 2722 times

[exxos]

Been messing about with the Atmel PLD for the past few hours.. Long story short, I'm having trouble even getting the STE 32MHz clock stable

So the bottom line is, should I produce another batch of this booster, it will just have to use the STE 32MHz clock. Though more testing will have to be done with current firmware fixes for that.

I'm not going to keep spending time on this as I have too many other projects which need my attention. So this project is being put on hold for the foreseeable future.

IMG_3812.JPG (149.63 KiB) Viewed 2663 times

[rubber_jonnie]

At present I'm struggling to be able to program anything but Lattice 22V10C GALS.

My TL866CS doesn't appear to support them, and right now I'm not able to re-program mine to be a TL866A, which does support Atmel 22V10C GALS.

I'm a bit loath to wipe my Lattice, as the booster is working and stable @40Mhz, but not if you want to use Ultrasatan. I guess I could back it up before I commit to trying a different program in the GAL, then I can at least go back.

At least I don't seem to have bricked the TL866 (Yet) but it's very frustrating that it just gets a reset fail now when I try and re-program it. It's all very annoying!

[rubber_jonnie]

Ok, so thanks to exxos for sending over a pre-programmed Atmel GAL so I could do the rework.

The 40Mhz oscillator was removed from the booster and a 32Mhz feed provided from U405 as per the original booster, and a few other minor tweaks done, and the plug in booster seems to be running fine at 32Mhz, as per the original solder in booster.

Speed seems on a par, and I now have no issues running my CosmosEx hard drive, which is essentially an Ultrasatan.

I tried copying files from floppy to hard disk, and vice versa, and running various apps off hard drive. Everything I tried ran fine, whereas when running at 40Mhz, the hard drive wouldn't work at all, with any attempt to run apps causing all sorts of problems.

So, a good result IMHO.

Here is the before rework pic:

Before.jpg (366.62 KiB) Viewed 2541 times

Here is the after rework pic:

IMG_20190311_223018.jpg (329.42 KiB) Viewed 2524 times

Running @ 8Mhz:

8mhz.jpg (275.82 KiB) Viewed 2541 times

And @ 32Mhz:

32Mhz.jpg (278.28 KiB) Viewed 2541 times

[exxos]

Thanks for the update and glad its now behaving.

[rubber_jonnie]

Thanks for the update and glad its now behaving.

Glad we got to here, it was nice to see all of our discussions turn into something useful.